Patent GB-719138-A (GB)
Title: Improvements in or relating to electrical impulse regenerators
Inventor: WRIGHT ESMOND PHILIP GOODWIN
IPC: H04Q1/36
Filed: 1951-09-19
Abstract: 719,138. Automatic exchange systems. STANDARD TELEPHONES & CABLES, Ltd. Sept. 12, 1952, [Sept. 19, 1951], No. 21963/51. Class 40 (4). An impulse regenerator able to receive impulses at one speed and transmit at another speed comprises two registers, means for transferring a train of impulses from the first to the second register, means inhibiting such transfer when a train is stored in the second register, and means to transmit a train from and clear the second register to re-enable the transfer means. Two or more digits may be stored in the first register. Registration of dialled digits into first register.- Closing the loop operates A, Fig. 2, which energizes B. The break of the first impulse releases A to energize Cl and operate tube IPB, Fig. 4, of a flip-flop so extinguishing IPA and extending +ve potential via terminal X to gate 1. As tube EB is normally conducting gate 1 opens to apply potential through gate 2 to fire the first tube DS1 of the digit-storage register DS. At the end of the break period A re-operates to fire IPA and extinguish IPB, so applying a pulse through gate 4 to cathode-follower CFA which applies a +ve-going pulse to the cathodes of all tubes of the register DS to move the pattern along one step in the manner described in Specification 663,574. The process repeats for each impulse. At the end of the digit, A and B are left energized and Cl releases slowly to restore flip-flop EA, EB, Fig. 4, and fire IPB. After a delay of 1 msec., IPA refires to give DS an additional step. Rapid movement of pattern to end of register.- Provided the second register is not transmitting to the outgoing line, tube EA biases gate 7 to pass tl pulses every 4 msecs., through gate 4 and pulse stepping circuit CFA to step the pattern rapidly along register DS. Transfer of digit to second register.-Tube CB of flipflop CA, CB operated at the energization of relay B. When the pattern has been moved to the end of register DS so that DS20 conducts, a t2 pulse midway between successive t1 pulses is passed through gate 11, Fig. 5, to fire tube TC 1 of the second register. The next tl pulse causes circuit CFD to move the pattern in TC one step, the process being repeated for the whole digit. Register DS continues to step after the transfer of the digit until D19 and D20 are both non- conducting when potential appears on terminals CFB, CFC. The next t2 pulse fires tube EB to prevent further stepping of DS. Transmission of digit to outgoing line.-When the tl pulses have moved the pattern along register TC so that TC10 fires, potential is applied to terminal TC10 so that a "beginning of impulse" pulse 12 fires tube OA so releasing the sending relay L which is normally energized. TC 10 also cuts off potential from TCP to halt movement of the pattern in the register. After 66 msecs. a pulse I1 restores flip-flop OA, OB to re-energize L to end the normal break impulse to line. Pulse I1 also steps register TC. The process repeats until TC10 is no longer conducting. The next I2 pulse fires tube SB so extinguishing SA and closing gate 17 to terminate sending. Relay CO, Fig. 2, holds up during the train and falls back slowly at the end to fire tube IDB of inter-digital pause flip-flop IDA, IDB, to disable gates 16, 17, 18, so preventing transmission to line while still permitting transfer from DS. After a delay of 600 msecs., tube IDA fires again. Storage of two digits in first register. If the next digit is much smaller the first digit may not be completely regenerated when the second digit is ready for transfer. When CI releases after the entry of the second digit it fires IPB and after 1 msec. IPA re-energizes to supply an extra stepping pulse to DS. As retransmission from TC has not been completed TCP potential is absent so that EA cannot fire and t1 pulses cannot step DS. When the third digit is dialled it is entered into register DS with one extinguished tube separating it from the second digit. Re-circulation of digit in first register.-When the first digit has been transmitted from register TC, OB fires and L operates to release CO, which fires EA and extinguishes EB. The second and third digits are then driven along DS. The second digit passes out of DS and is entered into TC in the manner previously described. The t2 pulse following this digit fires tube CA since DS19 is now conducting and DS20 is not. CB is thus extinguished to disable the input gate 11 of TC. The next t1 pulse steps the pattern to make DS20 conduct and the next t2 pulse fires DSI from DS20 over gate 25. Step by step the third digit is thus re-entered into DS. When both DS19 and DS20 are non-conducting CB and EB fire to halt the registration. Meanwhile the digit in TC has been driven to the end and is then transmitted to line. TC 10 then extinguishes to indicate that transfer can take place again. The circuit of Fig. 7 (not shown) is as described in Specification 713,902, [Group XL(c)].